Effect of graphene nanoplatelets on the microstructure and mechanical behavior of erbium-modified Al-7.5Si-0.5Mg alloy

In this study, the effects of adding erbium and graphene (separately and in combination) on the microstructure and mechanical properties of Al-7.5Si-0.5Mg alloy were investigated. Initially, the primary alloy was produced by casting in the form of ingots. To add graphene to the molten alloy, these particles were milled with aluminum powder for 3 h. Then 0.2, 0.4, and 0.6 wt% graphene, 0.2 wt% erbium, and finally, a combination of 0.2 wt% erbium with 0.4 wt% graphene were incorporated into the Al-7.5Si-0.5Mg alloy. The microstructure of the produced samples was examined using optical and electron microscopes, then the tensile and wear behaviors of the produced samples were examined. Finally, scanning electron microscopy (SEM) images were used to investigate the mechanisms of wear and failure. The results of this study showed that the addition of erbium and graphene modified the microstructure of the alloy and reduced the grain size of the alpha-aluminum. The best tensile and wear properties were obtained for the sample containing 0.2 wt% erbium + 0.4 wt% graphene. By adding this value to the Al-7.5Si-0.5Mg alloy, tensile strength and wear resistance were increased by 56% and 67%, respectively, compared to the control sample.